Not sure I can answer this specifically BUT I got upgraded. Not sure which JW you are staying at BUT if you can, stay at the Tomorrow Square..fabulous! The hotel actually starts on the 38th floor, the breakfast buffets are excellent, California grill and cigar bar are nice. The #2 Green line is less than 5' away in the People's Square, high end shopping is right on Nanjing West in between this property and the Ritz Portman (good steakhouse too (Portman's). El Cheapo market for knock-offs is a block away just past the overpass when you go left out of the hotel.
Also a bit late reply, and I cannot give you any information regarding likelyhood of an upgrade since I have not stayed there before, but I was booked on a one night deluxe king bed room stay last week and got upgraded to a newly renovated Executive Suite (one bedroom). Really nice property indeed.
View from the room on 43F.